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Friday, February 1, 2013

TCR-γ Expression in Primary Cutaneous T-cell Lymphomas.

TCR-γ Expression in Primary Cutaneous T-cell Lymphomas.

Jan 2013


*CNIO Lymphoma Group Departments of †Pathology ‡‡‡Dermatology, Fundación Jiménez Díaz Departments of ‡Dermatology §§§Pathology, Hospital Universitario 12 de Octubre §Pathology Department, Hospital de Torrejón de Ardoz Departments of **Dermatology ∥∥Pathology, Hospital Universitario Gregorio Marañón ***Dermatology Department, Hospital Universitario de Getafe, Getafe †††Immunohistochemistry Unit, Biotechnology Programme, CNIO, Madrid ∥Dermatology Department, Hospital Universitario Juan Canalejo, La Coruña ¶Dermatology Department, Hospital de San Juan, Alicante #Dermatology Department, Hospital Universitario Reina Sofía, Córdoba ††Dermatology Department, Hospital Universitario Virgen del Rocío, Sevilla §§Pathology Department, Hospital Universitario Marqués de Valdecilla, Santander ¶¶Dermatology Department, Hospital Virgen del Castillo, Murcia ##Dermatology Department, Hospital Santiago Apostol, Vitoria, Spain ‡‡UCSD Moores Cancer Center, La Joya, CA ∥∥∥Department of Dermatology, Research Unit Dermatopathology, Medical University of Graz, Graz, Austria.


Primary cutaneous γδ T-cell lymphomas (PCGD-TCLs) are considered a subgroup of aggressive cytotoxic T-cell lymphomas (CTCLs). We have taken advantage of a new, commercially available antibody that recognizes the T-cell receptor-γ (TCR-γ) subunit of the TCR in paraffin-embedded tissue. We have analyzed a series of 146 primary cutaneous T-cell lymphomas received for consultation or a second opinion in the CNIO Pathology Department. Cases were classified according to the World Health Organization 2008 classification as mycosis fungoides (MF; n=96), PCGD-TCLs (n=5), pagetoid reticulosis (n=6), CD30 primary cutaneous anaplastic large cell lymphomas (n=5), primary cutaneous CD8 aggressive epidermotropic CTCLs (n=3), primary cutaneous CTCL, not otherwise specified (n=4), and extranodal nasal-type NK/T-cell lymphomas primarily affecting the skin or subcutaneous tissue (n=11). Sixteen cases of the newly named lymphomatoid papulosis type D (LyP-D; n=16) were also included. In those cases positive for TCR-γ, a further panel of 13 antibodies was used for analysis, including TIA-1, granzyme B, and perforin. Clinical and follow-up data were recorded in all cases. Twelve cases (8.2%) were positive for TCR-γ, including 5 PCGD-TCLs, 2 MFs, and 5 LyP-Ds. All 5 PCGD-TCL patients and 1 MF patient died of the disease, whereas the other MF patient and all those with LyP-D were alive. All cases expressed cytotoxic markers, were frequently CD3/CD8, and tended to lose CD5 and CD7 expressions. Eight of 12 and 5 of 11 cases were CD30 and CD56, respectively. Interestingly, 5/12 TCR-γ-positive cases also expressed TCR-BF1. All cases analyzed were negative for Epstein-Barr virus-encoded RNA. In conclusion, TCR-γ expression seems to be rare and is confined to cytotoxic primarycutaneous TCLs. Nevertheless, its expression is not exclusive to PCGD-TCLs, as TCR-γ protein can be found in other CTCLs. Moreover, its expression does not seem to be associated with bad prognosis by itself, as it can be found in cases with good and bad outcomes.

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